1. Field of the Invention
The present invention relates to a well development tool and method that is used to remove ground water that is artificially contaminated or disturbed by the installation of the well and to help impacted ground water to be removed from the formation in the vicinity of the well.
2. Background of the Prior Art
Many industries, such as dry cleaners and gas stations, use various chemicals, such as heavy metals and chlorinated solvents, that if leeched into the ground, cause ground water contamination. Accordingly, the groundwater around potentially polluting sites is regularly monitored to assure that groundwater contamination does not occur or its movement is known. If contamination does occur, corrective action can be taken immediately to minimize environmental impacts.
A typical groundwater monitoring program involves the boring of several holes into the ground, to the level of the aquifer which can be up to 40 feet or more underground. After the boring of each hole, a well casing is dropped into the hole and a water sample is taken from the well casing. Typically, the well casing is made from PVC and is 1 to 2 inches or more in diameter. The lower end of the well casing—the end that is furthest in the ground—has a well casing screen which consists of a slotted PVC screen with narrow openings cut into the well casing. The boring of the ground and the sinking of the well casing into the ground causes disturbance within the soil, which if sampled immediately after the boring and sinking of the well casing, gives a false reading which is not truly reflective of the true groundwater conditions. The removal of the fine sediments is required before a sampling can be taken in order to get an accurate sample of the formation water.
Certain tools have been developed in order to “develop” the bored well in order to expedite the removal of the turbid water at the well casing in order to return the groundwater to equilibrium. Such tools remove the water that is in the immediate vicinity of the well casing which allows undisturbed water to percolate to the well casing area and replace the removed water. Such prior art devices include pumps and bailers that can advance the time when an accurate sample can be taken, although such devices are not without drawbacks.
Many such prior art devices are very expensive, with many bailers costing several hundred dollars. Additionally, such devices are bulky and are relatively difficult to use. Furthermore, if these devices are not used correctly, such as not being thoroughly cleaned between use in well casings, they can contaminate the water within the well casing in subsequently sampled wells. Even if correctly cleaned between use in well casings, such cleaning is labor intensive and time consuming. Additionally, current prior art devices only have the ability to pull water from within the casing upwards out of the casing.
Therefore, there exists a need in the art for a well development tool that helps expedite the clearing of the water at the base of a well casing so that a representative water sample can be taken, which well development tool addresses the above-stated concerns in the art. Specifically, the well development tool must be of relatively simple design and construction making it relatively inexpensive to manufacture, so that, advantageously, the well development tool can be discarded after developing a single well in order to eliminate problems with cross well contamination. The well development tool must be able to force groundwater downwardly in the casing in order to force water out of the screen, thereby effectively agitating the disturbed area and accelerating the removal of clay and silt sized particles contributing to the turbidity. The well development tool must be relatively compact in size and must be easy to use.